1. Field of the Disclosure
The present disclosure relates in general to hybrid vehicles, and more particularly to a hybrid powertrain for vehicles.
2. Description of the Related Art
Due to the a trend towards an increased use of diesel fuel for powering vehicles, a phenomenon know as dieselization, it is forecasted that the demand for diesel will increase while the demand for gasoline will be decrease. The trend towards dieselization is the result of both a price difference between gasoline and diesel as well as a difference in efficiency between spark and compression ignition powertrains. A vehicle that has lower fuel cost per mile driven is preferable by most drivers.
Because refineries cannot change the production ratio among diesel, kerosene and gasoline without major additional costs, in the future there may be a surplus of gasoline. In order to increase the demand for gasoline so that each of these products proportionally, it would be desirable to increase the efficiency of engines using gasoline so that they have the same efficiency as conventional modern diesel engines and so that the gasoline vehicle has the same cost per mile driven as a diesel vehicle. As an alternative to traditional gasoline currently available at the pump, unrefined gasoline, such as naphtha, can be run directly in a compression ignition engine without need of major hardware modifications as compared to gasoline. By using naphtha, the well to tank CO2 production is also minimized. Because of CO2 concerns and because of a surplus of light fraction, naphtha could be introduced into the market as a fuel for vehicles. However, naphtha is not yet readily available on the market.
As an alternative to spark or compression ignition powertrains, fully electric vehicles have been introduced. Conventionally, light and medium duty vehicles experience a significant number of transients in their typical driving cycle. Fully electric vehicles have an excellent transient response. However, fully electric vehicles can have a negative environmental foot print when coal, oil, or gas is used to generate the electricity that charges the vehicle.